Answer:
The amount invested at 7% is $12,000 while the amount invested at 10% is $8,000
Step-by-step explanation:
The given parameters are;
The total amount Hank invested = $20,000
The interest earned in one year = $1640
Hank invested part of the $20,000 at 7% interest and part of the $20,000 at 10%
Let the part invested at 7% = X and the part invested at 10% = Y, we have;
7% of X + 10% of Y = $1640 which gives;
0.07×X + 0.1×Y = $1640.....................(1)
X + Y = $20,000.................................(2)
Multiply equation (1) by 10 and subtract equation (1) from equation (2) to get;
X + Y - 10×(0.07×X + 0.1×Y) = $20,000 - 10×$1640
X - 0.7·X - Y - Y = $20,000 - $16,400 = $3,600
0.3·X = $3,600
X = $3,600/0.3 = $12,000
X = $12,000
Y = $20,000 - X = $20,000 - $12,000 = $8,000
Y = $8,000
Therefore, the amount invested at 7% = $12,000 and the amount invested at 10% = $8,000.
